<script>
import {defineComponent} from 'vue'

export default defineComponent({
    name: "Child",
    props:["num"],
    mounted(){
        console.log(this);
    }
})
</script>

<template>
    <div>
        <h3>Child|{{num}}</h3>
        <button @click="$emit('update:num',90)">修改父组件的数据状态num</button>
    </div>
</template>

<style scoped>

</style>